Accordingly, the inductance and capacity of the lateral branch of the transmitter is altered until the hot wire ammeter in the base of the aerial shows the largest possible current.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
They were all up to capacity, save the ammeter from the coils.
"Invaders from the Infinite"
John Wood Campbell
After we had done so we would call it an "ammeter" because it measures amperes.
"Letters of a Radio-Engineer to His Son"
John Mills